Plate-type air valve carburetor

ABSTRACT

In a plate-type air valve carburetor having a variable direction air flow, air foil means are provided to compensate for the apparent change in direction of air flow from intermediate to high air flow conditions. As the plate-type air valve aligns itself with the direction of air flow, the upstream edge of the air valve plate encounters the low pressure region below an air foil means and is rapidly snapped or drawn to its full open position. The air foil is positioned sufficiently upstream of the air valve so that its net effect on the apparent direction of air flow is negligible.

[451 Oct.3, 1972 United States Patent QuatranoBracke....v................. Tubb PLATE-TYPE AIR VALVE CARBURETOR.261/50 A .261/50 A ...261/50 A [72] Inventor: John Quatrano, WatkinsGlen, NY.

[73] Assignee: The Bendix Corporation [22] Filed:

Sto1tman.................

1/1957 Udale...................

June 1970 Primary Examiner-Tim R. Miles Attorney-Robert A. Benziger andFlame, Hartz, Smith and Thompson [21] Appl. No.: 44,302

ABSTRACT In a plate-type air valve carburetor having a variabledirection air flow, air foil means are provided to compensate for theapparent change in direction of air flow from intermediate to high airflow conditions. As the plate-type air valve aligns itself with thedirection of air flow,

[56] References Cited UNITED STATES PATENTS the upstream edge of the airvalve plate encounters the low pressure region below an air foil meansand is rapidly snapped or drawn to its full open 3 232 315 2/1966Morelli......................137/484 position. The air for] 1sposltloned sufficiently up- 3,512,508 5/1970Wmlder...................261/50 A stream of the air valve so that itsnet effec on the 2,443,464 6/1948 Leibmg et al. ...........261/50 Aparent direction of air flow is negligible 3,281,131 10/1966Mennesson..............261/50 A 2,082,293 6/1937Linga.......................26l/50 A 2 Claims, 4 Drawing Figures QP'ATENTEDnm m2 INVENTOR.

Qwfivfiuwt WITNESS ATTORNEY 1 PLATE-TYPE AIR VALVE CARBURETOR BACKGROUNDOF THE INVENTION 1 Field of the Invention The present invention isrelated to air valve carburetors in general and in particular to airvalve carburetors which employ a plate-type air valve to provide asignal indicative of the air velocity through the carburetor.

2. Description of the Prior Art The prior art shows that it is wellknown to employ a plate-type air valve in a carburetor 'to control theamount of fuel being provided to the air stream for ultimate supply tothe combustion chambers. of an internal combustion engine. Theplate-type air valve carburetors generally employ a flat platetypevalve, positioned to block the air intake of the carburetor, resilientlybiased to the closed. position. This valve is connected through suitablelinkage members to a fuel metering needle and fuel metering orifice suchthat movement of the valve from the closed to the open position willvary the position of the metering needle within the orifice. This hasthe ultimate result that a variable supply of fuel, typically gasoline,will be provided to the air stream downstream of the air valve. It hasbecome apparent, however, that a plain tube carburetor intake passageand a flat plate air valve cannotbe combined to provide a smoothvariation infuel and air flow, particularly at idle and part throttleoperation. The specific problem encountered is that as a flat plate-typeair valve begins to open, the first few degrees of angular rotationproduce a very large percentage change in the unobstructed air flow pathin the carburetor intake passage. It is, therefore, necessary to varythe fuel delivery over a wide range during the first increments of valvemovement and it is very difficult to achieve accurate control sinceslight variations due to manufacturing tolerance or the like will causelarge percentage variations in the fuel delivery. It has accordinglybeen determined that the contour of the intake passage in the vicinityof the plate-type air valve and the contour of the air valve itself maybe altered somewhat to provide the necessary smooth and accuratevariation of fuel flow in response to air flow. It thus becomes possibleto provide a proper air fuel mixture over a broad range of operatingconditions of the engine from the idle state to wide open throttle.

The use of the contoured air passage and contoured air valve hasgenerated another problem which becomes apparent only at the wide openthrottle setting; As the air valve begins to approach the wide openposition, which should be indicative of a high demand for fuel and airthe apparent direction of air flow past the air valve tends to be atsome angle to the real axis of the air passage due to the contours whichwere added to smooth out low air flow operation. In those engine demandsituations calling for increased fuel and air delivery to the engine,the air valve, having assumed a position which corresponds to a partthrottle setting, will not open to the position which will provide themaximum fuel delivery. In the transitionfrom the fully closed to thewide open throttle position, the air valve will assume some positioncorresponding to air flow at a part-throttle setting and will not, fromthat time forward, respond to increases in the velocity of air flowinvention to provide a means for urging the air valve beyond its nominalwide open setting into a true wide open setting corresponding withthemaximum air flow through the air passage of the carburetor.Furthermore, variations in air flow direction may occur from thegeometry of the associated air cleaner or the configuration ofsurrounding masses of engine, vehicle body and the like. It is,therefore, a still further object of the present invention to provide ameans for urging an air valve to a wide open position when changes indirection of the moving air stream otherwise prevent such movement. Inaddition, linkage modifications would introduce an undesirablehysteresis which would adversely affect the accuracy of the angularpositioning of the plate-type air valve. It is, therefore, an object ofthe present invention to provide a means to correct the angularpositioning of the plate-type air valve such that the angularpositioning of the air valve and the accuracy of the fuel metering areunaffected by hysteresis. It is a further object of this invention toprovide a means for opening the air valve from its previously describedmaximum position to a position which corresponds with the fuel demand ofthe engine at maximum air flows.

The problem of achieving proper positioning of the air valve in responseto air flow is also encountered in another area. As engine sizesincrease, air flow demands increase and the cross sectional area of theair intake passages increases. In order to reduce the height ofcarburetors, the air intake passages are kept as short as possible inorder to conform with todays automotive design standards of having a lowprofile of the vehicle. However, when the plate-type air valve havingthe necessary large surface area is rotated into alignment with the airflow, its dimension in the direction of air flow is sufficiently largethat the air valve extends well into the mouth, or intake, of thecarburetor air passage at one end while the downstream edge of the airvalve extends well down into the interior of the carburetor body. Thus,a significant portion of the plate-type air valve, which performs mostbeneficially in regions of laminar flow, must extend into the region ofturbulent air flows at the carburetor air intake. The result of thiscondition is that the air valve is prohibited from responding to thefull spectrum of air flow variations. It is, therefore, a further objectof this invention to provide means for improving plate-type air valveresponse to maximum and near maximum .air flows without adverselyaffecting fuel metering capabilities and without significantlyincreasing overall height of the carburetor.

SUMMARY OF THE INVENTION The presentinvention provides a plate-type airvalve carburetor with an air foil positioned near the intake of the airpassage so as to provide a zone of low pressure into which the extremeupstream or leading edge of the plate-type air valve may travel upon itsopening rotation. By providing the stationary air foil, the operation ofthe plate-type air valve is not affected until the air valve begins toenter the nearly wide open position, at which point the prior artvariable-direction air flow air valve carburetors had reached theirmaximum capability in fuel metering. Because the air foil is within theair stream at an extreme of the physical limitations upstream position,it has no overall effect upon the .air

flow characteristics of the carburetor. The air foil can be furtherrestricted in its size so as to have no effect upon the air valve untilthe air valve begins to approach the position which was a maximum forthe prior art air valve carburetors. The air foil, therefore, isoperative to affect the angular position of the plate-type air valvewith respect to the axis of the air intake passage over the full rangeof variations thereby permitting complete control of fuel meteringwithin the air valve carburetor without affecting the metering andlinkage characteristics. Furthermore, the physical height of this typeof carburetor, when mounted atop the engine as is the U. S. automotivepractice, can be maintained as low as possible due to the fact that theupper edge of the air valve, as it nears the region which would exposeit to the atmospheric air, comes into the influence of the air foil.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows my invention as applied toa plate-type air valve carburetor having a contoured air intake and acontoured plate type air valve.

FIG. 2 shows a fragmentary view of the air valve approaching the partthrottle position as it approaches the region influenced by the airfoil.

FIG. 3 shows in the second fragmentary view the air valve at the wideopen throttle position with the air valve under the influence of the airfoil.

FIG. 4 shows an elevational view of the air foil of FIGS. 1, 2 and 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1, 2 and3 and particularly to FIG. 1, my invention is illustrated as applied toan air valve carburetor, indicated generally as 10, having a body 11.The carburetor is comprised of air passage 12 extending through body 11and fuel supply means 14 associated therewith. Fuel from supply means 14is introduced into the air passage 12 via fuel supply conduit 16.Situated near the intake of air passage 12 is the air valve 18 which isshown as a contoured plate and is attached for angular movement aboutshaft 20. As illustrated in FIG. 1, the air valve is in the fully closedposition preventing air flow through conduit 12 and regulating the fuelsupply means so that there is no fuel flow through the fuel conduit 16.Air valve 18 is interconnected with fuel supply means 14 throughsuitable linkage means, not shown, such that the fuel delivery therefromis metered and controlled in response to the air valve position.

Air valve wide open assist means indicated generally by 21 are shown inFIG. 1 as being an air foil 22 positioned upstream of the air valve 18.Air foil 22 is illustrated in this embodiment as being a stationary airfoil of conventional design and is sufficiently small to present anegligible restriction to total air flow through the intake passage 12.Air foil 22 is attached by conventional means, shown as bolt 23, tosupport 25. Support 25 is adapted to position air foil 22 in anintercepting relationship with the upstream edge 24 of air valve 18 whenair valve 18 is rotated to its open position. The foil is, of course,somewhat upstream of this position as direct physical contact is notdesired but rather it is desired that the upstream edge 24 of air valve18 will intercept the low pressure region 26 normally associated with anair foil in a moving stream of air when the air valve 18 approaches wideopen position.

It will be seen that air intake passage 12 is provided with variouscontours 28, 30 such that the direction of air flow through conduit 12will vary from the mouth of passage 12 to the region below the fuelconduit 16. This variation, along with the contour in the plate-type airvalve itself, is operative to provide the necessary smooth transition infuel/air mixture flow from idle operation to the part throttleoperation. The prior art devices were substantially limited in theirwide-open throttle position to that shown in phantom lines in FIG. 1 asa result of the air valve attaining this position at part throttleoperation and increased air demand being supplied by that portion of theair intake passage 12 to the right (relative to FIG. 1 of the drawing)of the air valve pivot. Furthermore, the air being drawn through the airintake passage 12 will, due to the contour at 30, establish a laminarflow characteristic to the right (relative to FIG. 1 of the drawing) ofthe air valve pivot. This laminar flow will spread to fill the entireintake downstream of the air valve establishing a pressure balanceacross the downstream portion of the air valve which will prevent, inthe absence of my invention, further opening movement of the air valve.

FIG. 2 illustrates, in a fragmentary view, the air valve portion of theair intake 12. In this figure, air valve 18 has rotated counterclockwisein response to the passage of air through intake passage 12. A lowpressure region 26 has formed downstream of the air foil 22 but due tothe relatively slight velocity of air passing through intake passage 12,the region 26 is small and the upstream portion of valve 18 is notsufficiently close to region 26 to be influenced thereby. The air valvein this figure is approaching the position corresponding to partthrottle operation.

FIG. 3 illustrates the FIG. 1 embodiment as the air valve 18 reaches theposition corresponding to wide open throttle. The region 26 has grown insize while rotary movement of the air valve 18 and shaft 20 has broughtthe upstream edge 24 of air valve 18 into the region 26.

FIG. 4 shows an elevational view of the air foil 22 of the presentinvention. Air foil 22 is shown as an elongated inverted isoscelestriangle attached by suitable means, such as bolt 23 through a portionin proximity to the central portion of the base thereof to support 25.Thus the downward pointing apex of the triangle extends downwardly intothe interior of passage 12 (shown in FIGS. 1, 2 and 3). This shape ofair foil is particularly suited to an air valve having a dimension alongits axis in excess of the dimension perpendicular to the axis to theupstream edge of the air valve. By placing the apex generally downstreamfrom the base of the triangular air foil, the influence of the air foilon the air valve will increase as the air valve approaches the air foil.Conversely, as air flow through passage 12 decreases, the influence ofthe air foil on the air valve will be less pronounced and the air valvewill more readily assume a position remote from the air foil to properlyreflect the need for fuel to be metered in accord with optimum engineoperation.

The operation of my device will now be described with reference to FIGS.1, 2 and 3. Initially, the air foil 22 will be in the positionillustrated by solid lines in FIG. 1. This corresponds to the closedposition at which time there will be no fuel flow through the fuelconduit 16. Upon cranking of the associated engine, air will be drawnthrough the air intake passage 12 by the ordinary action of thecylinders and intake valve opening and closing. This flow of air willcreate a low pressure region downstream of the air valve 18 and willcause, through the differential area and differential pressures, thevalve to pivot about pivot 20 in a counterclockwise direction. Thisopening movement of the air valve 18 will initiate a fuel flow throughconduit 16 in the conventional fashion of air valve carburetors. Thisfuel flow through conduit 16 is a function of the angular position ofthe air valve 18 with respect to its closed position (as illustrated insolid lines in FIG. 1). As the air valve approaches the positionillustrated in FIG. 2, the engine will be in the part throttleoperational mode. That is to say that the engine will be operating at anintermediate power setting and will be demanding fuel and air insubstantially the relationship provided by the angular position of airvalve 18 and the unrestricted flow area provided within the conduit 12.As can be seen at this point, the air foil 22 is disturbing the flow ofair upstream of foil 22 but this turbulence in the air stream is notcommunicated to the downstream side of air valve 18 due to the fact thatair valve 18 is in a substantially blocking relationship across thisportion of air intake 12. During this phase of operation the fuelsupplied in accord with the air valve setting will be sub stantially asrequired by the engine through the conventional metering linkage (notshown). As the air, and consequently the fuel, demanded by the engineincreases as a result of increased engine speed, the air valve willpivot counterclockwise, relative to FIG. I, a more fully open positionas illustrated in FIG. 3. However, in the prior art devices of thistype, the air valve would reach a substantially balanced position atwhich point in time due to the curvature of the intake passage 12 andthe curvature of the air valve 18, the air valve would be axiallycentered relative to the direction of flow of air through the intakepassage and further increases in the flow of air would not operate toincrease the flow of fuel through conduit 16. In the prior art devicesof this type, this corresponded to a maximum fuel setting which wassomewhat below that necessary to permit the engine to achieve itsmaximum power capabilities. It is at this point in time where myinvention becomes applicable.

With specific reference to FIG. 3 it will be observed that as the airvalve 18 approaches a more fully wide open throttle position, theupstream edge 24 thereof approaches the low pressure region associatedwith air foil 22. As is known, the amount of and the extent of the lowpressure region associated with an air foil in a moving stream of air isa function of the velocity of that stream of air with respect to the airfoil as well as the curvature of the foil. As the amount of air beingingested by the engine through intake passage 12 increases in volume, itwill increase in velocity. This will produce a continuing increase inthe size of the low pressure region which is illustrated by number 26.By suitable design of the size, shape, and physical placement of airfoil 22 within intake passage 12, the exact point at which the edge 24of air valve 18 enters the low pressure region 26 can be varied. At thispoint In time,

a pressure differential will exist between the upstream portion of airvalve 18 and the downstream portion of air valve 18 such that anadditional counterclockwise torque will be generated on air valve 18 torotate it towards the more fully wide open position. The restrictionwhich is presented to the flow of air through air intake 12 will notvary beyond this point; however, the linkage which controls the amountof fuel being provided through conduit 16 will be informed of additionalcounterclockwise movement which will in turn increase the flow of fuelthrough fuel conduit 16.

Iclaim:

1. In combination with a carburetor of the type having fuel supplymeans, a body, an air intake passage passing therethrough and an airvalve situated therein to control the delivery of fuel to an air stream,wherein the air valve is a plate-type air valve adapted to rotate abouta pivot into substantial alignment with the axis of the intake passagein response to air flow therethrough whereby an edge of the air valvewill move from a position in proximity to a wall of said intake passageto a position upstream of the pivot, the improvement comprising:

air valve assist means situated in the air intake passage upstream ofthe air valve operative to assist movement of the air valve to themaximum open position including air foil means coupled to the air intakepassage operative to generate a low pressure zone within the air intakepassage in intercepting relationship with the upstream edge of the airvalve when the air valve is in the maximum open position.

2. In combination with a carburetor of the type having fuel supplymeans, a body, an air intake passage passing therethrough and an airvalve situated therein to control the delivery of fuel to an-air stream,wherein the air valve is a plate-type air valve adapted to rotate abouta pivot into substantial alignment with the axis of the intake passagein response to air flow therethrough whereby an edge of the air valvewill move from a position in proximity to a wall of said intake passageto a position upstream of the pivot, the improvement comprising:

air valve assist means situated upstream of the air valve operative toassist movement of the air valve to the maximum open position includingmeans for generating a low pressure zone within the air intake passagein the region of the upstream edge of the air valve and said means forgenerating a low pressure zone comprising air foil means attached to thehousing and positioned at the mouth of the air intake passage so that alow pressure zone will be generated thereby in an interceptingrelationship with the upstream edge of the air valve.

1. In combination with a carburetor of the type having fuel supplymeans, a body, an air intake passage passing therethrough and an airvalve situated therein to control the delivery of fuel to an air stream,wherein the air valve is a plate-type air valve adapted to rotate abouta pivot into substantial alignment with the axis of the intake passagein response to air flow therethrough whereby an edge of the air valvewill move from a position in proximity to a wall of said intake passageto a position upstream of the pivot, the improvement comprising: airvalve assist means situated in the air intake passage upstream of theair valve operative to assist movement of the air valve to the maximumopen position including air foil means coupled to the air intake passageoperative to generate a low pressure zOne within the air intake passagein intercepting relationship with the upstream edge of the air valvewhen the air valve is in the maximum open position.
 2. In combinationwith a carburetor of the type having fuel supply means, a body, an airintake passage passing therethrough and an air valve situated therein tocontrol the delivery of fuel to an air stream, wherein the air valve isa plate-type air valve adapted to rotate about a pivot into substantialalignment with the axis of the intake passage in response to air flowtherethrough whereby an edge of the air valve will move from a positionin proximity to a wall of said intake passage to a position upstream ofthe pivot, the improvement comprising: air valve assist means situatedupstream of the air valve operative to assist movement of the air valveto the maximum open position including means for generating a lowpressure zone within the air intake passage in the region of theupstream edge of the air valve and said means for generating a lowpressure zone comprising air foil means attached to the housing andpositioned at the mouth of the air intake passage so that a low pressurezone will be generated thereby in an intercepting relationship with theupstream edge of the air valve.